This course is designed to cover subjects in advanced high school chemistry courses, correlating to the standard topics as established by the American Chemical Society. This course is a precursor to the Advanced Chemistry Coursera course. Areas that are covered include atomic structure, periodic trends, compounds, reactions and stoichiometry, bonding, and thermochemistry.

FV

Very clear in the explanations provided, it is a complete course to really introduce to basic concepts of chemistry such as stechiometry, thermodynamic, atom structures and reactions.

TM

Jun 21, 2017

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This is a great course! Very well explained! It's managing to keep my attention on 100% and that's not an easy task for anybody. Thank you for sharing your knowledge with us!

À partir de la leçon

Week 3

Now that we know the structure of an atom, we can explore how atoms combine to form either molecular or ionic compounds. Then we will learn the rules of nomenclature that ensure that a compound is named according to IUPAC rules. We will end this unit by looking at quantitative relationships for compounds including the molar mass of and mass percent of an element in a compound.

Enseigné par

Dr. Allison Soult

Lecturer

Dr. Kim Woodrum

Sr. Lecturer

Transcription

In this problem we want to write the formula for chromium (III) oxide. The first thing we want to do is write the formula, or the symbol, for chromium. The roman numeral of III tells us that we have a three plus charge on chromium, and we have oxide, which means oxygen. And oxygen has a two minus charge in an ionic compound. We use our crisscross method here to get to Cr2O3, and I can check to make sure that that's reasonable by looking at the charges on my ions. I see I have two chromiums, each with a three plus charge, plus three oxygens each with a two minus charge, and when I add these up, I get a sum of zero, which is exactly what I want for an ionic compound that does not have a charge.